Needle thread supply for sewing machines



, Sept 12,1967 R. E. JOHNSON NEEDLE THREAD SUPPLY FOR SEWING MACHINES Filed Oct. 19, 1966 zlm \1 F vllrlarlllllllllrllllrlj Fig.4

INVENTOR. Ralph E. Johnson \d m? 7 5 s I 7:;

5 22 BY v WITNESS f United States Patent 3,340,837 NEEDLE THREAD SUPPLY FOR SEWING MACHINES Ralph E. Johnson, Boonton, N.J., assignor to The Singer gompany, New York, N .Y., a corporation of New ersey 7 Filed Oct. 19, 1966, Ser. No. 587,905 4 Claims. (Cl. 112254) The present invention relates to sewing machines, and in particular to a novel and improved arrangement for supporting a spool of needle thread directly on the sewing machine needle-bar together with mechanism for controlling the tension and take up of the needle thread.

An object of this invention is to provide an improved small, in expensive, efiicient and durable sewing machine.

Another object of this invention is to provide a sewing machine having an improved needle thread supply unit.

It is also an object of this invention to provide a needle thread supply unit of the above character which advantageously accommodates needle thread wound on a readily obtainable conventional bobbin of the type heretofore utilized for the bobbin thread of lock stitch sewing machine loop takers.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, cominations, and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

FIG. 1 is a vertical sectional view of a sewing machine embodying the present invention,

FIG. 2 is a sectional view taken substantially along line 22 of FIG. 1,

FIG. 3 is a sectional view taken substantially along line 33 of FIG. 2,

FIG. 4 is an enlarged view, partly in section, of the bobbin receiving cup and self adjusting thread tension device of the present invention, and

FIG. 5 is an enlarged view, partly in section, of a portion of the bobbin receiving cup and self adjusting thread tension device of the present invention.

Referring more specifically to the drawings the invention is disclosed as embodied in a sewing machine having a bed 12 and a standard 14 rising therefrom and merging into a bracket arm 16 that terminates in an overhanging head 18. A weighted base 20 is secured to the bed 12 to add weight and thereby stabilize the machine when it is operated. A sheet metal cloth plate 22 overlies the bed 12 and defines the work supporting surface of the machine.

Journaled for rotation longitudinally of the bracket arm 16 is a main shaft 24 upon which is mounted a gear 26 formed as part of a handwheel or crank 28 journaled upon a stud 30 fixed in the upper portion of the standard 14. The handwheel 28 has a handle 32 for rotating the same and thereby driving the main shaft 24. Journaled in the bed 12 on an axis parallel to the axis of the main shaft 24 is a bed shaft 34 which is connected for unitary rotation to the main shaft 24 by a belt 36 and pulleys 38 and 40.

The stitch forming mechanism of the machine includes a needle 42 and a nodding-type looper 44 that cooperates therewith in the formation of single thread chain stitches. The needle 42 is carried by a needle-bar 46, having an upper reduced portion 47, mounted in the head 18 for endwise reciprocation. The needle-bar 46 is actuated by a crank 48 mounted on the end of the main shaft 24, which crank includes a crank pin 50 that extends into a slot in a bracket 52 secured to the needle-bar 46. A spring biased resser-foot 54 is secured to the lower end of a presser-bar 56 journaled in the head 18 for endwise movement, the presser-bar being adapted to be manually raised or lowered by a lifting lever 58 pivotally mounted on a bracket 60 secured to the resser-bar.

The needle-bar 46 is driven in endwise reciprocation within the head 18 and cooperates with the other stitchforming instrumentalities as described more fully in United States Patent No. 3,099,973 issued to N. P. Lees on Aug. 6, 1963.

In accordance with the present invention, there is provided a cylindrical bobbin receiving cup 62 having a 1ower, solid base portion 64 and an upper, hollow, openended bobbin-receiving portion 66. The cup 62 is concentrically mounted upon the upper portion of the needlebar 46 and is secured thereto by a set screw 68 and has formed in the bottom face of the base portion 64 a transverse slot 70 and parallel vertical slots 72. An opening 74 in the top of the head 18 accommodates cup 62 and permits endwise reciprocation of the cup through the top of the head as the needle-bar 46 reciprocates. Mounted on the cup 62 is a self-adjusting spring biased thread tension device 75 adapted to provide the desired degree of tension in thread T, and described more fully below.

The upper bobbin-receiving portion 66 of the cup 62 includes a wall 76 having formed therein a thread guide slot 78, and a pair of opposed indentations 80. The rim of the wall 76 has formed thereon a flange 84 that projects radially outward from the wall but extends only part way around the circumference of the wall. Formed in the flange 84 is a vertical presser-bar guiding notch 86 and a pair of spring retaining holes 88, while directly below the flange 84 a window 90 is cut out of the Wall 76. Directly beneath the window 90 a lip 92 projects laterally from the lower end of the base portion 64 and includes a resser-bar guiding hole 94 for the presserbar 56. The upper portion 66 of the bobbin receiving cup 62 is adapted to receive a' bobbin 96, formed of suitable tansparent material, having spaced flanges 97, upon which is wound a supply of the thread T. The transparency of the bobbin allows the operator at any time visually to gauge the amount of the thread T on the bobbin without removing the bobbin. The bobbin 96 is rotatably mounted on a low friction cylindrical bearing 98 in turn mounted on the reduced portion 47 of the needle-bar 46.

The thread tension device 75 comprises two spaced parallel legs 100 which are substantially U-shaped. One of the parallel legs 100 includes an integrally formed lever 102 extending upwardly therefrom, as seen more clearly in FIGS. 2, 4 and 5. One end portion 104 of the parallel legs 100 supports a pin 106 which pin is adapted to pivot in the slot 70, in the bottom face of the base portion 64, while the end portions 104 are adapted to slidingly engage the parallel vertical slots 72 (FIGS. 3 and 4). The other end portions of the parallel legs 100 are joined by a thread tension arm 108 (FIGS. 4 and 5), the length of the arm being slightly less than the width of the window 90 in the wall 76, the arm itself normally protruding through the window 90 and pressing against the thread T wound on the bobbin 96. The thread tension device 75 is held in place and biased by a pair of coil springs 110 which are hooked by one end to slots 112 in the end portions 104 of the legs 100 and by the other end in the spring retaining holes 88 in the flange 84 of the wall 7 6.

To load the thread supply cup 62 the operator must grasp the lever 102 and pivot the parallel legs 100 out wardly away from the cup 62 against the tension of the springs 110. This removes the thread tension arm 108 from within the upper hollow portion 66 of the cup 62 and allows the operator to slide the bobbin 96 onto the cylindrical bearing 98 through the opening in the top of the cup 62. The operator may then release the lever 102 and the tension supplied by the springs 110 will pivot the legs 100 thereby pulling the thread tension arm 108 through the window 90 and up against the thread T wound on the bobbin-96. Choice of the springs 110 determines the degree of thread tension which will be provided by the thread tension device. The bias supplied by the springs 110 provides that a constant pressure will be applied to the thread T by the arm 1&8 regardless of the changing amount of thread on the bobbin as the thread is unwound. The bobbin 96 is prevented from jumping out of the cup 62 during the operation of the machine by reason of the positioning of the end portions 105 and the tension arm 108 between the spaced flanges 97 of the bobbin.

To remove the bobbin 96 the operator need merely move the tension arm 108 clear of the flanges 97, by pivoting the legs 100, and'then slip the tip of his thumb and index finger through the indentations 8G in the Wall of the cup 62 and under the upwardly facing flange of the bobbin 96 and thereafter lift the bobbin out of the cup.

Numerous alternations of the structure herein disclosed Will suggest themselves to those skilled in the art. However, it is to be understood that the present disclosure relates to a preferred embodiment of my invention which is for purposes of illustration only and not to be construed as a limitation of the invention. All such modifications which do not depart from the spirit of the invention are intended to be included within the scope of the appended claims.

Having thus described the nature of the invention, what I claim herein is:

1. In a sewing machine having a frame including a bed, a standard rising from the bed, a hollow bracket arm overhanging said bed and secured to said standard, a head formed at the end of said bracket arm and stitch forming mechanism including a needle-bar and a needle carried by said needle-bar, said needle-bar being mounted in said head for endwise reciprocation, means for rotatably mounting a thread wound bobbin on said needle-bar, said means including a bobbin receiving cup having a bobbinreoeiving end, said bobbin receiving cup being removably mounted upon the upper portion of said needle-bar, and a spring biased thread tension unit, means pivotally mounting said thread tension unit on said bobbin receiving cup, whereby said bobbin receiving cup provides a support for the thread wound bobbin and said thread ten sion device and said bobbin receiving cup and thread tension device reciprocate with said needle-bar.

2. A sewing machine as set forth in claim 1 wherein said bobbin receiving cup includes a wall and said wall has formed therein a window and said thread tension unit includes a thread tension arm which protrudes through the window and engages the thread wound bobbin, whereby said thread tension arm is adapted to tension the thread drawn from the thread wound bobbin.

3. A sewing machine as set forth in claim 2, wherein the upper portion of said wall includes finger indentations and a thread guide slot, and a lever arm for moving said thread tension arm toward or away from the thread wound bobbin.

4. In a sewing machine having a frame including a bed, a standard rising from the bed, a hollow bracket arm overhanging said bed and secured to said standard, a head formed at the end of said bracket arm and stitch forming mechanism including a needle-bar and a needle carried by said needle-bar, said needle-bar being mounted in said head for endwise reciprocation and having an upper reduced segment, the top of said head having a cup clearance opening formed therein; a cylindrical bobbin receiving cup having a hollow upper portion and a solid lower portion, said hollow upper portion having an open end, said cylindrical bobbin receiving cup being mounted concentrically on the upper portion of said needle-bar with said reduced segment of the needle-bar protruding upwardly into said hollow upper portion, a low friction bearing mounted on said reduced segment of said needle-bar, said hollow upper portion receiving a thread wound bobbin rotatably mounted on said low friction bearing, the wall of said hollow upper section having a window formed therein, a thread guide slot and finger indentations, the bottom face of said solid lower portion having formed therein a transverse slot, a spring biased thread tension unit mounted on said cylindrical bobbin receiving cup, said thread tension unit including a pair of substantially U-shaped parallel legs, a pivot pin joining one pair of the leg ends and a thread tension arm joining the other pair of the leg ends, a lever connected to one of said parallel legs, a pair of coil springs connected by one end to said parallel legs and by the other end to said cylindrical bobbin receiving cup, said transverse slot receiving said pivot pin and said window allowing the passage therethrough of said thread tension arm, whereby said thread tension arm may be moved into and out of said hollow upper portion through said window by utilizingsaid lever to pivot said parallel legs against the bias of said coil springs and said tension arm being biased by the coil springs to tension the thread drawn from the thread wound bobbin.

References Cited FOREIGN PATENTS 213,997 10/1909 Germany.

JORDAN FRANKLIN, Primary Examiner.

G. KRIZMANICH, Assistant Examiner. 

1. IN A SEWING MACHINE HAVING A FRAME INCLUDING A BED, A STANDARD RISING FROM THE BED, A HOLLOW BRACKET ARM OVERHANGING SAID BED AND SECURED TO SAID STANDARD, A HEAD FORMED AT THE END OF SAID BRACKET ARM AND STITCH FORMING MECHANISM INCLUDING A NEEDLE-BAR AND A NEEDLE CARRIED BY SAID NEEDLE-BAR, SAID NEEDLE-BAR BEING MOUNTED IN SAID HEAD FOR ENDWISE RECIPROCATION, MEANS FOR ROTATABLY MOUNTING A THREAD WOUND BOBBIN ON SAID NEEDLE-BAR, SAID MEANS INCLUDING A BOBBIN RECEIVING CUP HAVING A BOBBINRECEIVING END, SAID BOBBIN RECEIVING CUP BEING REMOVABLY MOUNTED UPON THE UPPER PORTION OF SAID NEEDLE-BAR, AND A SPRING BIASED THREAD TENSION UNIT, MEANS PIVOTALLY MOUNTING SAID THREAD TENSION UNIT ON SAID BOBBIN RECEIVING CUP, WHEREBY SAID BOBBIN RECEIVING CUP PROVIDES A SUPPORT FOR THE THREAD WOUND BOBBIN AND SAID THREAD TENSION DEVICE AND SAID BOBBIN RECEIVING CUP AND THREAD TENSION DEVICE RECIPROCATE WITH SAID NEEDLE-BAR. 